The present invention relates to a method, and more particularly to a method of making a shoe sole of thermoplastic materials.
Rubber materials have been widely used as shoe sole material because of their wear resistance and elasticity. U.S. Pat. No. 4,418,483 to Fujita et al. discloses a method of manufacturing sole material, wherein a midsole layer and outsole layer of synthetic resin sheets are superposed and put between mold pieces, and hot pressed into one piece by fusion. The piece of united layers should be cut at each position P in order to form a plurality of cut out portions. Each cut out portion is laterally divided along line 1 by a splitting machine and cut into the required shape. It is very complicated and time consuming to cut the piece of united layers into cut out portions and to cut each cut out portion into the required shape. In addition, a crosslinking agent is required to crosslink the layers together. A further process is required to put a trademark or a pattern onto the peripheral surface of the shoe sole after cutting processes. This is complicated.
U.S. Pat. No. 1,400,146 to Eggers et al. discloses an art of making hollow rubber articles, wherein two sheets of rubber stocks are provided and are firmly united in order to form a plurality of articles. In this method, no foamable materials are added in the rubber stocks so that the rubber stocks do not foam and expand and so that the mold cavities for receiving the rubber stocks do not need to have a reduced size than the hollow rubber articles to be made. The rubber stocks should be severed by the edges of the mold members so that stock trimmings 15a are cut off and are received in the channels or recesses 16 which should be provided in the molds. In addition, a vacuum or suction system is required to hold the rubber stock or rubber sheet in place in each socket.